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Published on: June 30, 2021
Distinction between 2'- and 3'-Phosphate Isomers of a Fluorescent NADPH Analogue Led to Strong Inhibition of Cancer
Raoul Manuel1, Michelle de Souza Lima1, Sébastien Dilly1
1Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France.
Abstract:
Specific inhibition of NADPH oxidases (NOX) and NO-synthases (NOS), two enzymes associated with redox stress in tumor cells, has aroused great pharmacological interest. Here, we show how these enzymes distinguish between isomeric 2'- and 3'-phosphate derivatives, a difference used to improve the specificity of inhibition by isolated 2'- and 3'-phosphate isomers of our NADPH analogue NS1. Both isomers become fluorescent upon binding to their target proteins as observed by in vitro assay and in vivo imaging. The 2'-phosphate isomer of NS1 exerted more pronounced effects on NOS and NOX-dependent physiological responses than the 3'-phosphate isomer did. Docking and molecular dynamics simulations explain this specificity at the level of the NADPH site of NOX and NOS, where conserved arginine residues distinguished between the 2'-phosphate over the 3'-phosphate group, in favor of the 2'-phosphate.
Insights
Researchers developed a specific inhibitor for NADPH oxidases (NOX) and NO-synthases (NOS) by utilizing isomeric differences. The 2’-phosphate isomer showed greater efficacy, with molecular simulations explaining the enhanced specificity for redox stress modulation.
Area of Science:
- Biochemistry
- Pharmacology
- Molecular Biology
Background:
- NADPH oxidases (NOX) and NO-synthases (NOS) are key enzymes involved in redox stress within tumor cells.
- Targeting these enzymes offers significant pharmacological potential for cancer therapy.
- Understanding enzyme-inhibitor interactions is crucial for developing specific and effective drugs.
Purpose of the Study:
- To investigate the specificity of inhibiting NOX and NOS enzymes using isomeric NADPH analogue derivatives.
- To explore the potential of 2'- and 3'-phosphate isomers of NS1 for targeted enzyme inhibition.
- To elucidate the molecular basis for differential inhibition by these isomers.
Main Methods:
- Synthesis and application of 2'- and 3'-phosphate isomers of the NADPH analogue NS1.
- In vitro enzyme assays to measure inhibitory effects.
- In vivo imaging to observe isomer binding to target proteins.
- Molecular docking and dynamics simulations to analyze binding interactions.
Main Results:
- Both 2'- and 3'-phosphate isomers of NS1 exhibited fluorescence upon binding to NOX and NOS.
- The 2'-phosphate isomer demonstrated more significant effects on NOX- and NOS-dependent physiological processes compared to the 3'-phosphate isomer.
- Molecular simulations revealed that conserved arginine residues in the NADPH binding site of NOX and NOS preferentially interact with the 2'-phosphate group, explaining the observed specificity.
Conclusions:
- Isomeric differentiation of 2'- and 3'-phosphate groups is a viable strategy for enhancing the specificity of NOX and NOS inhibitors.
- The 2'-phosphate isomer of NS1 is a more potent inhibitor due to favorable interactions within the enzyme's active site.
- These findings provide a foundation for designing novel, highly specific therapeutic agents targeting redox pathways in diseases like cancer.
